Duncan JB-Weird Issue

[larryguitar]

I have a JB that's bounced around a bit, and had some issues. I've tried a few times to repair it, and tried again today, but it still has the same issue:

The pickup had some of the coil wires disconnected, so I have reattached them a few times. This last time, I meter'd each coil and got around 8K (didn't record it, just made sure it was ballpark OK for a JB) connnected the N finish to the S start and got around 17K. Wired it back up to the four wire that it originally had (just taped off the red and white, only needed the straight HB tone) and it still showed around 17K at the end of the leads.

Installed it in a guitar, tip to ring on a cable plugged into the jack showed around 17K, figured we're off to the races.

And we are-sort of. Both coils are live (tapping on screws and slugs shows sound) and it sounds like a humbucker (not a single coil of a humbucker), but the output is WAY lower than any of the (ahem, 'several') JB's I have in other guitars. WAY lower.

I'm stumped; besides the resistance (which I think precludes a short, right) what can I check to narrow the issue down?

Thanks,

Larry

 

[Clint 55]

Re: Duncan JB-Weird Issue

It's wired out of phase with itself. One of the coils' start and finish is mixed up to the hookup leads.

 

[larryguitar]

Re: Duncan JB-Weird Issue

It's wired out of phase with itself. One of the coils' start and finish is mixed up to the hookup leads.

That makes sense, Clint-both coils working, humbucking but thin.

Any idea what the color codes for an SD humbucker's coils might be, or a wiring diagram for the coils to the four-wire, so I can trouble-shoot?

Thanks again!

Larry

 

[Clint 55]

Re: Duncan JB-Weird Issue

For the slug coil, black goes to black and white goes to white. For the screw coil, black goes to green and white goes to red.

For the coil leads, blacks are starts and whites are finishes. For the hookup leads, the north (slug) start is black and the north finish is white. The south (screw) start is green and the south finish is red.

If there are only black coil leads, check to see which lead comes from the inside of the the coil - that's the start. And the lead which comes from the outside of the coil is the finish.

 

[larryguitar]

Re: Duncan JB-Weird Issue

For the slug coil, black goes to black and white goes to white. For the screw coil, black goes to green and white goes to red.

For the coil leads, blacks are starts and whites are finishes. For the hookup leads, the north (slug) start is black and the north finish is white. The south (screw) start is green and the south finish is red.

If there are only black coil leads, check to see which lead comes from the inside of the the coil - that's the start. And the lead which comes from the outside of the coil is the finish.

Awesome-thanks very, very much!

Larry

 

[Clint 55]

Re: Duncan JB-Weird Issue

No prob!

 

[GrilledChickenSalad]

Re: Duncan JB-Weird Issue

Any idea what the color codes for an SD humbucker's coils might be, or a wiring diagram for the coils to the four-wire, so I can trouble-shoot?

https://forum.seymourduncan.com/showthread.php?t=98432&highlight=2+conductor+4

Coil lead wires from from left to right and their corresponding wire of a 4-conductor lead...

1- White Stud(Left Balck on a 59/Seth/PG) = White
2- Black Stud(Bottom of coil on a 59/Seth/PG) = Black
3- White Screw(Left Black on a 59/Seth/PG) = Red
4- Black Screw(Bottom of coil on a 59/Seth/PG) = Green

On a 2 condutor lead:
1 & 3 are soldered together
2 is HOT
4 is soldered to baseplate

 

[larryguitar]

Re: Duncan JB-Weird Issue

As an update; rewired this pickup with inner coil leads directly connected, and outer coil leads connected to a two-conductor wire; same result. Humbucking, but thin.

Reversed leads, same result.

Even flipped the magnet (no idea why, just throwing s*** at the wall at this point) without any difference.

I'm stumped; I can't think of another way to wire this thing. And it still reads 16+K.....

Larry

 

[OLDERBUDWISER]

Re: Duncan JB-Weird Issue

As an update; rewired this pickup with inner coil leads directly connected, and outer coil leads connected to a two-conductor wire; same result. Humbucking, but thin.

Reversed leads, same result.

Even flipped the magnet (no idea why, just throwing s*** at the wall at this point) without any difference.

I'm stumped; I can't think of another way to wire this thing. And it still reads 16+K.....

Larry

JB is pretty cheap, chit can it and get another or something else. Lot of aggravation it seems

 

[Masta' C]

Re: Duncan JB-Weird Issue

Try a different mag...one you know is fully charged. There's a chance the original magnet got degaussed somehow, especially if the pickup was treated/handled/stored poorly.

 

[beaubrummels]

Re: Duncan JB-Weird Issue

I'm stumped; I can't think of another way to wire this thing. And it still reads 16+K.....

16k is resistance through the coil wire. It’s just telling you how much wire is on the bobbin. That has a smaller affect on the output you are getting, or not getting, than people think.

 

[larryguitar]

Re: Duncan JB-Weird Issue

16k is resistance through the coil wire. It’s just telling you how much wire is on the bobbin. That has a smaller affect on the output you are getting, or not getting, than people think.

Understood, but it should mean the coils aren't shorted or damaged, right? And I'll give the magnet a try-I can't really think of anything else it could possibly be, but I'm a newbie on all this.

Thanks,

Larry

 

[frankfalbo]

Re: Duncan JB-Weird Issue

I’m trying to understand what you’ve tried already. Last I’m reading, it sounds like you’ve made it a 2 conductor, hardwired the coil junction, and then only tried reversing the hot and ground as a means of phase inversion.

But have you gone back to the coils, chosen ONE of the coils, and reversed the start and finish of only one of the coils? If not, it sounds as though the two coils are out of phase with one another, and all you’re doing by swapping hot and ground is a global phase flip, not fixing the two coils’ relationship to one another.

 

[larryguitar]

Re: Duncan JB-Weird Issue

I’m trying to understand what you’ve tried already. Last I’m reading, it sounds like you’ve made it a 2 conductor, hardwired the coil junction, and then only tried reversing the hot and ground as a means of phase inversion.

But have you gone back to the coils, chosen ONE of the coils, and reversed the start and finish of only one of the coils? If not, it sounds as though the two coils are out of phase with one another, and all you’re doing by swapping hot and ground is a global phase flip, not fixing the two coils’ relationship to one another.

Yes, that is correct. I'll try this (swapping the 'start/finish') connections and then report back.

I really appreciate the responses and help.

Thanks,

Larry